Metal surface



Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE Noni-Wing. Application July 31, 1934, Serial No. 737,760

Claims. (CH. 91-681) This invention-relates to metal surfaces. The invention is particularly directed to imparting texture, patina, andlike effects to metallic surfaces such as surfaces of the non-corrosive or stainless steels, chromium plated metals and the like, which normally have no oxide film or at least none visible to the eye and are therefore limited in popularity because of their harsh, blank and shiny metallic appearance.

It is an object of the invention to provide a metal surface which stands up permanently and requires no polishing, and which at the same time has permanent texture, patina and shading effects to whatever predetermined extent may be desired. A further object is to provide such a surface having any desired permanent pattern effect.

The surfaces to be treated may be smooth, continuous surfaces, without relief, or. may be of three-dimensional relief configuration, and it is an object of the invention to provide, on articles of incorrodible metallic character having relief configuration, an appearance of contrasted brilliance on the high or exposed parts and ofdarkness and shading in the recessed parts similar to that which is obtained by aging and polishing of relief design articles made of silver, brass or other oxidizable metals.

It is a particular object of my invention to pro.

Vide an article with relief configuration surface which shall have the same sort of graduated brilliance and darkness as aged, polished silver, and which will keep this attractive appearance permanently without requiring the usual recurrent polishing. 35 According to my invention one takes a body of stainless steel, chromium plated metal, or any other substantially stainless metallic substance,.

and applies upon the surface of same a partial coating of minute spots of metal which can be stained or oxidized, such as silver, for example. .These spots may be applied in any of a great many ways, for example, by means of a conventional Schoop gun, by spattering through a screen,

an open space of the foundation metal, or they may be so generously applied that they all overlap each other, leaving only minute apertures between them through which the foundation metal can be seen. In practice the arrangement will generally be somewhere between these extremes, with some but not all of the spots overlapping. Whatever the particular arrangement, the foundationsurface of stainless metal is provided with an open-work plating of oxidizable'm'etal applied thereon, the particles of applied metal and the visible areas of foundation metal each being too small to be separately visible on ordinary inspection in use, whereby the surface has an appearance of a tone intermediate the appearance of the two metals. The greater the distance from whichthe surface is to be viewed the larger the spots may be, just so long as they are small enough to give'a general tone effect to the eye. Circular spots on magnification resemble coins, scales or discs spaced apart on the foundation surface.

The term metal as used in the claims is intended to designate briefly not only pure metals but alloys, mixtures, and other metallic substances.

Such a surface may be made up in many unique attractive effects, not only by varying the proportion of stainless surface which is covered bythe spots and by varying the shape of the spots but also by arranging the spots in patterns. For instance, this method of treating the surface is adaptable to having a stencil interposed when the spots are being applied, giving any desired pattern to the finished surface.

When anarticle has been produced in this way it may be handled as the finished product at that stage, in which case the spots of silver or other oxidizable metal will oxidize slowly from atmose pheric exposure. Alternatively an article soproduced can be given an oxidizing or other staining treatment at the factory in which case its appearance is permanent and unchanging from the time it leaves the factory.

Whether the oxidation is from the gradual action'of the atmosphere or from a treatment at the time of manufacture, the surface remains brilliant where the stainless metal is exposed, and darkened from oxidation at thespots of oxidizable metal on the surface. I

The final result is a permanent, resistant article having a softened, textured surface which may range from almost black through gun-metal color to complete brilliancy, and from very low to very high light reflection depending on the choice of oxidizable metal, on how large a proportion and which part of the surface is constituted by oxidizor most of those in the recessedparts.

able metal, and also on whether the original surface is or is not relieved. This treatment is par- For relief design articles suchas trays,'

pitchers, goblets, ash trays, ornamental panels, etc., this method of surfacing. can be used to give all the beauty of tone belonging to articles made of solid oxidizable metal or covered with a continuous plating of oxidizable metal.

Moreover as this -type of plating is Worn off with handling and polishing it keeps its attractive appearance, for the dark tone of the recessed spotted parts blends gradually into the brilliancy of the raised parts due to the spots being worn off individually and irregularly. In contrast an article of stainless metal covered with a continuous plating of silver shows sharply defined edges between the parts where the plating remains and where it is worn off, which spoils its appearance.

Furthermore it is in the purview of my invention to apply a partial coating of spots of silver or other relatively soft oxidizable metal to a stainless steel article having relief design, oxidize the spots, and then buff the article so as to completely wear off all or most of the spots of softer metal on the high parts and leave all This treatment gives a finished article graduated from brilliant high lights to dark recesses, which will keep this appearance permanently without any polishing. The oxidizing may be done either before or after the bufling.

Use of silver on stainless steel is merely an illustrative example. The invention extends to the formation of a metal surface in the manner outlined above by applying spots of any oxidizable metal onto a surface of any non-oxidizable metal. The former might be of silver, lead, aluminum, brass, or any of a great many others. Furthermore, the darkening or coloration of the applied metal can be brought about by other means than oxidation, as by chemical reactions which will not affect the foundation metal at all,

or at least not affect it in the same way, or it can even be by the selective absorption of dyes. For example, aluminum spots can be sprayed onto a polishedsurface of stainless steel and the whole dipped in a vegetable dye which would color the aluminum particles while having little or no effect on the stainless steel.

Where I use the expression oxidizable-metal" in the claims I mean a metal which merely upon prolonged exposure: to the atmosphere will undergo a surface reaction which visibly and noticeably alters the appearance of its surface, as for example in the case of silver, brass, and copper, whose surfaces become darkened by oxidation upon prolonged exposure to the atmosphere. Where I use'the expression stainless metal or "non-oxidizable metal in the claims I mean a metal which merely upon prolonged exposure to the atmosphere will not undergo any surface reaction which visibly and noticeably alters the appearance of its surface, as for example stainless steel orchromium.

Moreover many -of theadvantages here outlined could be achieved by reversing the process and applyingan open-work plating of stainless steel or other non-oxidizable metal, onto a foundation surface of oxidizable metal, such as aluminum, with the applied particles and the visible areas of foundation metal each being too small to be separately visible on ordinary inspection in use.

Articles in accordance with my invention are relatively inexpensive, and, in addition to having an attractive appearance of the same sort as a silver surface, this kind of surfacing does not break down as ordinary plating does.. The. separate spots may wear off individually but will not peel off like a continuous plated surface may do. This is because the individual spots of silver or the like are so small that the differences in electric potential and coeflicients of expansion and is not confined to the examples which I have given above to illustrate and explain the invention. I

I claim:

- 1. An article of manufacture having a foundation surface of stainless metal and anopen-work plating of oxidizable metal applied thereon, the particles of applied metal and the visible areas of foundation metal each being too small to be separately visible on ordinary inspection in use whereby the surface has an appearance of a tone intermediate the appearance of the two metals.

'2, An article of.manuf acture having a foundation surface of oxidizable metal and an openwork plating of stainless metal applied thereon, the particles of applied metal and the .visible areas of foundation metal each being too small to be separately visible on ordinary inspection in use whereby the surface has an appearance of a tone intermediate the appearance of the two metals.

3. An article of manufacture having a foundation surface of one metal and an open-work plating of another metal applied thereon, the particles of applied metal and the visible areas of foundation metal each being too small to be separately visible on ordinary inspection in use whereby the surface-has an appearance of a tone intermediate the appearance of the two metals, one of said metals being oxidizable and the other stainless. I

4. An article of manufacture having a foundation surface of stainless steel and an open-work plating of silver applied thereon, the particles applied silver and the visible areas of foundation stainless steel each being too small to be separately visible on ordinary inspection in use whereby the surface has an appearance of. a tone intermediate the appearance of .the two metals.

5. A relief configuration article ,of manufacture having a foundation surface of stainless metal and an open-work plating f oxidizable metal on the recessed portions thereof, the particles. of applied metal and the visible areas of foundation metal in such recessed portions being each too small to be separately visible on ordinary inspection in use whereby such recessed portions have an appearance of a tone interbeing free from applied metal.

' stainless steel 6. Process of imparting permanent patina. to a metal surface comprising applying thereto particles of a second metal, too small to be separately visible on ordinary inspection in use, in an open-work arrangement breaking up the remaining exposed surface of the foundation metal into areas too small to be separately visible on ordinary inspection in use, one of said metals being nonoxic lizable and the other being oxidizable.

7. Process of imparting permanent patina to a non-oxidizable metal comprising applyingthereto particles of an oxidizable metal, too small to be separately visible on ordinary inspection in use, in an open-work arrangement breaking up the remaining exposed surface of the nonoxidizable metal into areas too small to be separately visible on ordinary inspection in use.

8. 'Process of imparting permanent patina to comprising applying thereto particles of silver, too small to be separately visible on ordinary inspection in use, in an openwork arrangement breaking up the remaining exposed surface of the stainless steel into areas too small to be separately visible on ordinary inspection in use.

9. Process of producing a permanently varitoned article comprising applying minute particles of oxidizable metal, too small to be separately visible on ordinary inspection in use, to a relief configuration article oi non-oxidizable metal in an open-work arrangement breaking up the remaining exposed surfaces of the nonposed surfaces of-the stainless steel into areas too small to be separately visible on ordinary irispec-= tion in use, and bufling the article to the extent of. completely removing the silver from the most exposed portions oi the surface.

HENRY H. HARRIS 

